Hofsjökull, large glacier in central Iceland that covers a circular area (384 square miles [994 square km]) nearly 25 miles (40 km) in diameter. It rises to a height of 5,791 feet (1,765 metres) in the centre, and its meltwaters feed several rivers, including the Héradhsvötn, Thjórsá, Ölfusá, and Blanda.